Risk factors for venous thrombosis after discharge from medical hospitalizations: the Medical Inpatient Thrombosis and Hemostasis study

• Published in: Journal of thrombosis and haemostasis Vol. 23; no. 7; pp. 2190 - 2197
• Main Authors: Thomas, Ryan M., Sparks, Andrew D., Wilkinson, Katherine, Gergi, Mansour, Repp, Allen B., Roetker, Nicholas S., Smith, Nicholas L., Muthukrishnan, Preetika, Martin, Karlyn, Zakai, Neil A.
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01.07.2025
• Subjects: Adult; Aged; Aged, 80 and over; comorbidity; Female; Hemostasis; Hospitalization; Humans; Incidence; Inpatients; Length of Stay; Male; Middle Aged; outpatients; Patient Discharge; Risk Assessment; Risk Factors; Time Factors; venous thromboembolism; Venous Thromboembolism - diagnosis; Venous Thromboembolism - epidemiology; Venous Thrombosis - diagnosis; Venous Thrombosis - epidemiology; length of stay; outpatients; comorbidity; patient discharge; venous thromboembolism
• ISSN: 1538-7836; 1538-7836
• DOI: 10.1016/j.jtha.2025.04.005

Many studies on hospital-associated venous thromboembolism (VTE) do not specifically assess the risk factors for events after discharge. This study aimed to identify risk factors for postdischarge venous thromboembolism (PD-VTE) after a medical hospitalization. Patients discharged from a medical hospitalization at the University of Vermont Medical Center between January 2010 and September 2019 were followed up for inpatient and outpatient VTE events for up to 90 days. Age-adjusted, sex-adjusted, race-adjusted, and length of stay–adjusted Cox models estimated the hazard ratios (HR) and 95% CIs for potential risk factors for PD-VTE. Among 22 599 admissions, there were 180 PD-VTE events (90-day cumulative incidence of 0.8%). The median time from discharge to PD-VTE was 29 days. Of previously identified in-hospital VTE risk factors, only history of VTE (HR, 3.34; 95% CI, 2.26-4.93) and active cancer (HR, 3.13; 95% CI, 2.31-4.23) were associated with increased risk of PD-VTE. Compared to <2-day hospital stays, longer hospital stays (HR, 1.84; 95% CI, 1.23-2.75, for 6-10 days and HR, 1.64; 95% CI, 0.93, 2.90, for 11+ days) were associated with increased risk of PD-VTE. Both mortality (HR, 1.22; 95% CI, 1.06-1.41 per SD higher) and readmission (HR, 1.30; 95% CI, 1.13-1.50, per SD higher) Elixhauser comorbidity indices were associated with increased risk of PD-VTE. Risk factors for VTE after discharge from medical hospitalization differ from risk factors for in-hospital VTE. These data support that characteristics of the hospitalization influence PD-VTE risk, and if indicated, PD-VTE risk should be assessed at discharge.